I would have liked this more if it didn't have the harem tag. Emily's enough.

It's not much of a harem. The Rabbit girl only wants carrots, the tamer girl is too young, the fire girl never outright shown any romantic interest and the same goes for Emily. The only girl that is outright fawning over him is the receptionist. So she has my vote. I could be wrong though. If there is evidence of one of them showing romantic interest I need to see it. Chapter and page number would be excepted as evidence.